That first photo is from an earlier program, the Gemini-Titan training program of 1965. In the photo, Neil Armstrong and fellow astronaut David Scott are training in “water egress.”

Here’s an earlier photo, from 1964, of astronauts training in the desert. This remarkably fresh looking photo features (left to right) Frank Borman, Neil Armstrong, John Young and Deke Slayton:

Here’s Armstrong and Scott again, training in 1966 for the Gemini VIII mission, in the ocean:

Just prior to their trip to the moon, astronauts Armstrong, Aldrin and Collins from Apollo 11 sit inside the Mobile Quarantine Facility (MQF). They’d just been training in Hawaii, and Neil Armstrong is cradling a ukelele:

Back from the moon, the astronauts are greeted by President Richard M. Nixon while in quarantine in the MQF, 24 July 1969:

The Apollo 11 astronauts in a parade in New York:

The Apollo 11 astronauts in a parade in Mexico City:

Here are the boys at Mission Control, celebrating the success of Apollo 11:

As I said, much of the NASA collection is about Apollo 11. There are a few shots of some of the other moon landings, including this 1971 photo of Charles Duke, Jr., who was part of the Apollo 16 mission (the next-to-last Apollo mission):

For more historic NASA photos, visit their Flickr pages. You’ll even see some photos from the various missions to Mars, including this 1976 shot of the planet’s surface, courtesy of Viking II: